Lagoon City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lagoon City clear sky chart from 2005-11-06 to 2024-04-25.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	16% 10% 4 7% 6% 3 5% 5% 5% 7% 33%	83636
	Night	16% 12% 5% 8% 6% 3 5% 4 5% 6% 30%	85449
Transparency	Day	50% 6% 13% 20% 10% 1	83347
	Night	54% 6% 12% 18% 9% 1	85273
Seeing	Day	18% 6% 23% 31% 17% 5%	13971
	Night	20% 7% 27% 31% 13% 2	23130

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	16% 16% 8% 10% 7% 3 4 3 4 4 24%	2517
	11th to 20th	Day	11% 17% 8% 14% 10% 5% 5% 5% 5% 5% 15%	2658
	21st to end	Day	18% 20% 6% 10% 6% 3 5% 4 4 5% 18%	3124
February	1st to 10th	Day	13% 15% 6% 12% 8% 4 6% 6% 4 5% 20%	1710
	11th to 20th	Day	11% 13% 8% 10% 8% 4 4 5% 4 7% 26%	1663
	21st to end	Day	17% 14% 5% 9% 8% 4 4 4 5% 6% 23%	1441
March	1st to 10th	Day	18% 12% 4 7% 6% 3 5% 4 5% 5% 31%	3432
	11th to 20th	Day	11% 14% 6% 9% 7% 4 5% 5% 4 6% 28%	3480
	21st to end	Day	14% 8% 3 6% 6% 3 5% 5% 5% 6% 41%	3815
April	1st to 10th	Day	19% 10% 4 7% 7% 4 5% 4 5% 5% 31%	2261
	11th to 20th	Day	21% 7% 3 5% 5% 3 4 4 5% 5% 38%	2328
	21st to end	Day	19% 9% 3 6% 6% 3 4 4 4 6% 36%	2394
May	1st to 10th	Day	17% 6% 3 6% 7% 3 5% 5% 6% 7% 35%	2369
	11th to 20th	Day	14% 7% 3 6% 5% 3 5% 4 5% 6% 43%	2478
	21st to end	Day	13% 5% 2 5% 5% 3 5% 5% 6% 8% 43%	2725
June	1st to 10th	Day	17% 7% 2 6% 4 3 4 5% 5% 8% 39%	2520
	11th to 20th	Day	13% 5% 2 5% 5% 3 4 6% 6% 9% 41%	2578
	21st to end	Day	15% 5% 3 6% 4 3 5% 5% 6% 9% 39%	2700
July	1st to 10th	Day	9% 4 2 4 5% 3 6% 5% 7% 9% 47%	2638
	11th to 20th	Day	10% 6% 3 5% 5% 3 6% 5% 6% 9% 43%	2520
	21st to end	Day	10% 4 2 6% 6% 4 7% 6% 7% 10% 38%	2632
August	1st to 10th	Day	11% 4 2 5% 4 3 5% 6% 6% 8% 44%	2327
	11th to 20th	Day	10% 6% 2 5% 5% 5% 5% 6% 6% 9% 42%	2303
	21st to end	Day	11% 6% 3 5% 6% 3 5% 5% 6% 9% 40%	2480
September	1st to 10th	Day	13% 6% 2 6% 6% 4 4 4 5% 8% 41%	2160
	11th to 20th	Day	13% 5% 2 5% 5% 3 4 4 5% 7% 47%	2075
	21st to end	Day	15% 7% 3 7% 6% 4 4 5% 5% 6% 39%	1931
October	1st to 10th	Day	21% 8% 2 6% 5% 4 4 5% 4 7% 33%	1800
	11th to 20th	Day	24% 9% 4 8% 6% 3 4 5% 5% 7% 25%	1800
	21st to end	Day	26% 11% 4 7% 7% 3 5% 5% 5% 5% 22%	1980
November	1st to 10th	Day	17% 12% 5% 6% 6% 4 5% 5% 5% 6% 29%	1559
	11th to 20th	Day	18% 11% 5% 10% 5% 4 6% 5% 7% 7% 22%	1520
	21st to end	Day	21% 18% 5% 8% 7% 3 5% 5% 6% 6% 17%	1520
December	1st to 10th	Day	17% 19% 7% 13% 8% 3 5% 4 4 5% 14%	1520
	11th to 20th	Day	20% 15% 5% 8% 6% 3 5% 4 5% 6% 22%	1906
	21st to end	Day	27% 18% 6% 11% 6% 3 4 4 4 4 14%	2772
January	1st to 10th	Night	17% 20% 8% 12% 9% 4 4 4 4 5% 14%	4429
	11th to 20th	Night	14% 12% 8% 15% 12% 5% 5% 4 4 5% 16%	4298
	21st to end	Night	19% 17% 7% 10% 7% 4 4 4 4 5% 20%	4532
February	1st to 10th	Night	13% 16% 6% 11% 8% 4 7% 5% 5% 6% 19%	2470
	11th to 20th	Night	13% 13% 7% 9% 7% 4 5% 5% 5% 6% 26%	2403
	21st to end	Night	15% 14% 5% 10% 7% 3 5% 4 5% 6% 27%	2006
March	1st to 10th	Night	17% 12% 4 8% 6% 3 5% 4 5% 6% 32%	3408
	11th to 20th	Night	13% 14% 6% 8% 6% 3 4 4 5% 6% 31%	3479
	21st to end	Night	16% 7% 4 6% 5% 3 4 6% 6% 7% 37%	3817
April	1st to 10th	Night	21% 10% 3 7% 7% 2 5% 5% 5% 5% 30%	1919
	11th to 20th	Night	18% 8% 3 7% 6% 3 3 4 5% 8% 36%	1815
	21st to end	Night	16% 9% 3 8% 7% 3 5% 4 5% 6% 35%	1665
May	1st to 10th	Night	18% 6% 3 5% 5% 3 4 4 5% 9% 38%	1589
	11th to 20th	Night	13% 6% 2 5% 4 3 4 5% 5% 7% 45%	1415
	21st to end	Night	11% 5% 2 4 4 3 5% 4 5% 10% 49%	1550
June	1st to 10th	Night	15% 6% 3 5% 6% 3 5% 5% 6% 9% 38%	1440
	11th to 20th	Night	10% 5% 2 5% 5% 3 4 5% 7% 9% 45%	1374
	21st to end	Night	13% 7% 3 6% 6% 3 5% 5% 6% 6% 40%	1260
July	1st to 10th	Night	7% 4 3 5% 5% 2 5% 4 5% 7% 54%	1318
	11th to 20th	Night	10% 6% 3 5% 3 3 5% 4 6% 9% 47%	1440
	21st to end	Night	10% 4 2 4 4 3 6% 5% 8% 8% 46%	1682
August	1st to 10th	Night	8% 5% 2 5% 5% 4 4 6% 6% 7% 49%	1611
	11th to 20th	Night	7% 5% 2 5% 5% 3 5% 5% 6% 9% 49%	1598
	21st to end	Night	12% 5% 1 6% 6% 3 6% 5% 5% 8% 43%	1858
September	1st to 10th	Night	12% 5% 2 5% 5% 3 5% 5% 6% 8% 44%	1800
	11th to 20th	Night	12% 5% 2 4 5% 3 3 4 6% 8% 48%	1880
	21st to end	Night	16% 7% 3 6% 5% 3 4 4 5% 6% 42%	2029
October	1st to 10th	Night	19% 6% 3 6% 6% 4 5% 5% 6% 6% 33%	2160
	11th to 20th	Night	22% 10% 4 8% 6% 4 5% 4 5% 5% 27%	2160
	21st to end	Night	22% 14% 3 7% 7% 3 4 4 5% 7% 24%	2376
November	1st to 10th	Night	20% 10% 4 6% 5% 3 5% 4 5% 7% 32%	2516
	11th to 20th	Night	17% 15% 5% 7% 7% 3 5% 5% 5% 7% 24%	2660
	21st to end	Night	21% 14% 5% 9% 7% 3 6% 5% 5% 7% 18%	2660
December	1st to 10th	Night	21% 19% 7% 10% 6% 3 5% 5% 4 4 15%	2660
	11th to 20th	Night	17% 18% 6% 11% 8% 4 4 4 5% 5% 19%	3288
	21st to end	Night	27% 19% 6% 12% 7% 3 4 4 3 4 11%	4884

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	64% 5% 15% 10% 7%	2518
	11th to 20th	Day	71% 5% 10% 9% 5%	2658
	21st to end	Day	69% 6% 10% 9% 6% 1	3124
February	1st to 10th	Day	64% 4 11% 16% 4 1	1710
	11th to 20th	Day	58% 5% 11% 16% 8% 1	1672
	21st to end	Day	62% 4 11% 16% 7%	1441
March	1st to 10th	Day	53% 5% 16% 15% 10%	3435
	11th to 20th	Day	54% 4 13% 20% 8% 1	3480
	21st to end	Day	43% 5% 12% 22% 17% 2	3815
April	1st to 10th	Day	53% 5% 10% 20% 11% 1	2261
	11th to 20th	Day	48% 4 10% 23% 15% 1	2328
	21st to end	Day	50% 5% 10% 19% 13% 3	2394
May	1st to 10th	Day	48% 5% 10% 22% 14% 2	2369
	11th to 20th	Day	42% 5% 11% 26% 15% 1	2482
	21st to end	Day	38% 7% 15% 23% 14% 2	2725
June	1st to 10th	Day	43% 6% 12% 24% 14% 1	2520
	11th to 20th	Day	38% 7% 13% 25% 16% 1	2578
	21st to end	Day	40% 7% 16% 24% 13% 1	2700
July	1st to 10th	Day	31% 8% 14% 28% 18% 2	2567
	11th to 20th	Day	35% 6% 17% 30% 10% 1	2445
	21st to end	Day	39% 9% 14% 26% 12% 1	2485
August	1st to 10th	Day	35% 7% 18% 27% 11% 2	2314
	11th to 20th	Day	35% 8% 19% 26% 11% 1	2303
	21st to end	Day	38% 7% 17% 26% 11% 1	2480
September	1st to 10th	Day	40% 6% 14% 28% 10% 2	2160
	11th to 20th	Day	37% 6% 15% 31% 12%	2075
	21st to end	Day	46% 7% 13% 26% 8%	1931
October	1st to 10th	Day	51% 6% 13% 19% 11% 1	1800
	11th to 20th	Day	58% 6% 15% 16% 5% 1	1800
	21st to end	Day	62% 7% 12% 13% 5%	1980
November	1st to 10th	Day	55% 6% 15% 16% 7%	1559
	11th to 20th	Day	59% 8% 12% 14% 6% 1	1520
	21st to end	Day	66% 8% 12% 11% 3	1520
December	1st to 10th	Day	74% 6% 10% 8% 2	1520
	11th to 20th	Day	63% 8% 11% 11% 6%	1906
	21st to end	Day	74% 5% 9% 9% 2	2772
January	1st to 10th	Night	72% 5% 10% 10% 3	4429
	11th to 20th	Night	68% 6% 12% 10% 4 1	4298
	21st to end	Night	67% 5% 13% 10% 5% 1	4532
February	1st to 10th	Night	66% 5% 10% 16% 4 1	2470
	11th to 20th	Night	58% 5% 12% 17% 7%	2405
	21st to end	Night	57% 5% 12% 18% 8%	2006
March	1st to 10th	Night	54% 4 12% 20% 9% 1	3418
	11th to 20th	Night	53% 4 16% 18% 7% 2	3480
	21st to end	Night	44% 6% 10% 23% 16% 1	3817
April	1st to 10th	Night	55% 4 9% 19% 11% 1	1919
	11th to 20th	Night	46% 5% 9% 22% 16% 2	1815
	21st to end	Night	50% 6% 11% 15% 16% 1	1665
May	1st to 10th	Night	44% 5% 12% 19% 17% 3	1589
	11th to 20th	Night	40% 4 10% 25% 18% 3	1416
	21st to end	Night	33% 6% 16% 25% 17% 3	1551
June	1st to 10th	Night	42% 6% 11% 23% 15% 2	1440
	11th to 20th	Night	35% 6% 13% 24% 20% 1	1374
	21st to end	Night	43% 6% 14% 22% 14% 1	1260
July	1st to 10th	Night	29% 6% 12% 29% 22% 3	1280
	11th to 20th	Night	34% 5% 14% 31% 16%	1392
	21st to end	Night	33% 6% 14% 30% 15% 1	1588
August	1st to 10th	Night	32% 7% 19% 28% 14% 1	1600
	11th to 20th	Night	31% 7% 19% 26% 16% 1	1598
	21st to end	Night	39% 7% 13% 28% 12% 1	1858
September	1st to 10th	Night	36% 8% 16% 27% 12% 1	1800
	11th to 20th	Night	35% 5% 14% 32% 14% 1	1880
	21st to end	Night	43% 5% 13% 28% 10%	2029
October	1st to 10th	Night	49% 7% 12% 20% 12% 1	2160
	11th to 20th	Night	58% 6% 11% 18% 6%	2160
	21st to end	Night	61% 7% 9% 13% 9% 1	2376
November	1st to 10th	Night	52% 6% 13% 21% 8% 1	2516
	11th to 20th	Night	59% 7% 12% 14% 6% 2	2660
	21st to end	Night	65% 9% 14% 10% 2	2660
December	1st to 10th	Night	71% 7% 10% 9% 3	2660
	11th to 20th	Night	68% 6% 12% 12% 3	3288
	21st to end	Night	79% 4 7% 7% 2	4884

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	18% 14% 34% 22% 11% 2	180
	11th to 20th	Day	19% 10% 37% 24% 9% 1	221
	21st to end	Day	26% 5% 28% 31% 8% 1	297
February	1st to 10th	Day	21% 13% 32% 27% 6% 1	270
	11th to 20th	Day	16% 10% 37% 32% 4	270
	21st to end	Day	26% 13% 28% 30% 2	244
March	1st to 10th	Day	18% 5% 34% 35% 7%	460
	11th to 20th	Day	16% 12% 31% 32% 10% 1	460
	21st to end	Day	25% 5% 27% 30% 12% 1	506
April	1st to 10th	Day	20% 5% 29% 34% 9% 2	460
	11th to 20th	Day	26% 5% 26% 27% 12% 4	452
	21st to end	Day	20% 8% 24% 33% 12% 4	437
May	1st to 10th	Day	22% 4 20% 33% 15% 5%	423
	11th to 20th	Day	16% 2 19% 38% 19% 5%	447
	21st to end	Day	15% 2 18% 33% 23% 8%	485
June	1st to 10th	Day	18% 3 17% 38% 21% 3	450
	11th to 20th	Day	14% 4 20% 34% 21% 8%	508
	21st to end	Day	15% 4 20% 37% 20% 5%	630
July	1st to 10th	Day	9% 3 13% 39% 29% 7%	562
	11th to 20th	Day	14% 2 13% 33% 28% 9%	444
	21st to end	Day	8% 2 16% 40% 27% 7%	488
August	1st to 10th	Day	10% 3 13% 33% 31% 10%	446
	11th to 20th	Day	11% 3 13% 28% 33% 12%	439
	21st to end	Day	13% 5% 15% 30% 27% 10%	495
September	1st to 10th	Day	10% 6% 19% 31% 23% 12%	450
	11th to 20th	Day	11% 3 14% 32% 26% 13%	450
	21st to end	Day	16% 6% 21% 29% 20% 8%	450
October	1st to 10th	Day	22% 4 24% 26% 14% 10%	450
	11th to 20th	Day	24% 13% 26% 28% 7% 2	450
	21st to end	Day	29% 11% 27% 24% 8% 1	495
November	1st to 10th	Day	22% 15% 24% 28% 10% 1	234
	11th to 20th	Day	21% 12% 35% 24% 6% 2	180
	21st to end	Day	25% 14% 30% 29% 2	180
December	1st to 10th	Day	22% 16% 31% 28% 3 1	180
	11th to 20th	Day	25% 21% 29% 20% 3 2	180
	21st to end	Day	27% 13% 35% 21% 5%	198
January	1st to 10th	Night	23% 11% 36% 21% 7% 2	760
	11th to 20th	Night	26% 8% 30% 28% 8% 1	760
	21st to end	Night	21% 7% 27% 36% 9% 1	836
February	1st to 10th	Night	21% 6% 35% 32% 6%	760
	11th to 20th	Night	19% 9% 33% 32% 7% 1	743
	21st to end	Night	21% 7% 34% 32% 6%	628
March	1st to 10th	Night	21% 5% 31% 37% 7%	760
	11th to 20th	Night	18% 6% 35% 33% 7% 1	760
	21st to end	Night	20% 4 27% 36% 13%	836
April	1st to 10th	Night	25% 4 27% 35% 8%	760
	11th to 20th	Night	20% 5% 28% 33% 12% 2	691
	21st to end	Night	19% 5% 27% 35% 13% 1	555
May	1st to 10th	Night	22% 2 17% 39% 17% 2	509
	11th to 20th	Night	15% 6% 21% 39% 19% 1	354
	21st to end	Night	12% 2 19% 42% 22% 3	389
June	1st to 10th	Night	16% 4 23% 39% 17% 2	360
	11th to 20th	Night	11% 3 21% 42% 21% 2	360
	21st to end	Night	15% 4 16% 39% 24% 2	360
July	1st to 10th	Night	9% 2 16% 43% 27% 3	350
	11th to 20th	Night	11% 3 20% 38% 25% 3	348
	21st to end	Night	11% 1 15% 44% 27% 1	502
August	1st to 10th	Night	10% 2 16% 38% 31% 4	537
	11th to 20th	Night	7% 2 17% 37% 32% 5%	534
	21st to end	Night	13% 3 18% 35% 28% 3	670
September	1st to 10th	Night	13% 4 19% 35% 23% 7%	720
	11th to 20th	Night	15% 3 17% 33% 24% 8%	720
	21st to end	Night	20% 6% 19% 30% 19% 7%	720
October	1st to 10th	Night	21% 5% 29% 26% 16% 3	720
	11th to 20th	Night	25% 9% 30% 25% 9% 2	720
	21st to end	Night	29% 11% 29% 26% 5%	792
November	1st to 10th	Night	24% 10% 27% 27% 11% 1	740
	11th to 20th	Night	24% 13% 34% 21% 7% 1	760
	21st to end	Night	26% 14% 32% 23% 5%	760
December	1st to 10th	Night	30% 14% 32% 19% 4	760
	11th to 20th	Night	23% 14% 36% 21% 5% 1	760
	21st to end	Night	30% 9% 34% 22% 3	836

Page generated at 2024-04-22 09:25:40. Version ac07

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